Mechanical hammer



MLMAQ@ 4 Sheets-Sheet 1 R. GoLDscHMlDT MECHANICAL HAMMER meg April 14,1921 Feb. i@ 1924i.,

0m romy;

f//A/AM M. 19, 1924,l mmm@ f R. GOLDSCHMIDT MECHANICAL H AMMER FiledApril 14, 1921 4 Sheets-Sheet 2 Feb.. 19, 1924. www@ IR. GOLDSCHMIDTICAL HAMMER Filed April '14. 1921 4 Sheets-Sheet 3 Mii/zelf e5.-yew/ffm:

'5 Wadaf MSM/mdf? W @M6 W imm, (a

Feb., 19 1924. 194841,49@

R. GOLDscHMlD-r MECHANICAL HAMMER' Filed April 14. 1921 4 Sheets-Sha??l4 Wg 4.5, `Ffgfg 74- agg/.5.

Patented Feb. i9, 1924.

nii-an srarns RUDOLF GOLDSCHMIDT, OF BERLIN, GERMANY, SSIGNOR T0 DETTEKNSKFZ FCWGS- AKTIESELSK :.:l OF ORDRUZP, CHARLOTTENLUND, DENMARK, ACOMPANY F DEN- MECHANICAL HAMMER.

Application tiled April 14, 1921. Serial No. 461,446.

To all whom t may concern.:

Be it known that l, RUDOLF Gonnsoninn'r, a German citizen, resi ing at45 Linden Allee, West End, Berlin, Germany, have 1ne vented new anduseful improvements in Mechanical Hammers, of which the following is aspecification.

This invention relates to mechanical hammers and consists essentially ineffecting ic the storage of energy in the tup by the reaction of thebearings of an element or elements movable relatlvely to the tup.

ln order that the invention may be more clearly understood referencewill hereinafter i be made to` the accompanying drawings whereon:

Fig. 1-0ld form-is a diagrammatic View of a known type of mechanicalhammer.

Fig. 2 is a. side view partly in sect-ion 2c showing one form of thepresent invention. Fig. 8 is a side Aview partly in section taken atright angles to Fig. 2.,

Figs. 4, 5 and 6 are diagrammatic illustrations of the hammer shown inFig. 2 in 2e three different positions.

Fig. 7 is a sectional view of a modied form of mechanical hammer or piledriver.

Fig. 8 illustrates a further modified construction of the presentinvention applied au to a hand hammer or percussive hand tool. Figs. 9and 10 are detail sectional views of the mechanism shown in Fig. 8

Figure 11 is a sectional view showing a further modified construction ofthe imas proved mechanism, and Figure 12 is a sectional view on the lineZ-Z of Figure 11.

Fig. 13 is a fragmentary view of the improved mechanism applied to areciprocatory tup of a hammer and Fig. 14 is an end e View of themechanism shown in Fig. 13.

Figs. 15 and 16 are detail views of the pin-and-slot mechanism employedin the mechanism shown in Figs. 13 and 14.

Referring to Fig. 1 which illustrates a 4.5 common form of actuatingmechanism for the tup V of a hammer, driven by means of a crank A andconnecting rod'B, it is usual to interpose a spring U between thecrosshead of the connecting rod and the tup in 5e order to give thelatter slight freedom of movement relative to the positive movement ofthe crosshead. The provision of a spring however presents structuraldifficulties, as

part of the power is absorbed by the spring instead of being imparted tothe tup. rlhe construction is therefore always comparatively large andheavy and subject to considerable vibrations.

The object of the present invention is to drive the tup of the hammer bysimple mechanical means so that it shall have sufficient freedom ofmovement and to provide an arrangement in which the highest possiblevelocity shall be attained at the momentwhen the 4blow takes place.

In order to attain this object the forces reacting on the crank bearingl (Fig. 1) are uti ized to drive the hammer. ing to the presentinvention and as shown in Fig. 2, the crank bearing K is mounted on thetup V which can reciprocate vertically between the guides C. At itsupper end the tup V carries the crank A which is rotatable in thebearings K and driven by a spring Y. By means of a universal couplingand longitudinal flexible shaft, the driving mechanism does not impedethe movement of the tup. The spring Y is wound up by the motor D. rThefunction of the spring will be hereinafter `more fully described.

By means of the connecting rod B, the crank is connected toy a weight W'which is freely movable vertically in a. guide in the tup V. Hrepresents an anvil on which a block T is to be forged. When the crankA. is rotated, the weight `W is reciprocated and reacts through thecrank A upon the bearings K. As the bearings are movable with the tup V,the tup is thus` set in reciprocatory motion. lVithin certain limits ofspeed the operation will be as follows; reference being made to Figs. 4,5 and 6:-

Assuming the tup V to be in its lowermost position and resting upon thework F and assuming that the weight W has passed its point of maximumVelocity fu, as in Fig. 4f, and that it is retarded by the force P1,then a reaction P2 will be produced in the crank 'bearing K, thereaction F2 being equal to the force P1. The reaction P2 raises the tupand varies in magnitude, reaching its maximum when the weight W hasreached its uppermost position and is again moving downwardly (Fig. 5).'l` he force F2 changes in direction when the weight W has passed itsmiddle position (Fig. 6) thereafter till Accord- 1 I adjustable by meansof a tooth if the tup is loaded not only by the force l of gravity butby other downwardly acting forces, such as a spring. In the case ofhammers which are to operate horizontally or in a vertically upwarddirection, this spring serves not only to increase the force of the blowbut also to absorb the recoil. y

Fig. 7 illustrates a resilient or spring` controlled hammer or piledriver. The driving shaft R mounted in the tup V actuates the weight Wby means of an eccentric A and rod B. A spring X acts upon the tu wheeland gearing from an external pulley S2. A lower spring U is provided formoderating and regulating the force of the blow. Normally this spring isdisposed so low down that the distance a is greater than the distance b,so that the s ring U is ineffective. If the height of t e spring U isadjusted by rotation of the wheel S2, part of the kinetic energy of thetup V will be taken up by the spring U and in the extreme position, thetup V will no lon er strike the pile T.

The spring X s ould be so arranged that it acts on the tup with apractically constant force. This may be attained by imparting to thespring such an initial compression that its force is only slightlyaltered on further compression. If the stroke for example is tencentimetres, a spring would be selected compressed by say one metre inlength before insertion in the casin In the case of hand hammersaconstant orce is important as a spring of insufficient initial tensionwould lead to undesirable vibrations. ,Cranks and connecting rods arenot alwa s the best means for actuating the weig t W. In the firstplace, on account of the vibrations in the bearings set up b the blowsof the tu rof the hammer, the iameter of the shag; will generallyrequire to be sogreat that the crank and connecting rod must be re lacedby an eccentric. In such case in or er to suppress vibrations at rightan les to the direction of the blow, the weig t W may be driven by meansof two sets of eccentrics which rotate at the same angular velocity butin opposite directions.

Fig. y28 illustrates a hand hammer having 'l the aforesaidmodifications. The tup V is direction.

guided in a casing C. R is a cross pin fixed on the tup and on which theeccentrics A2 and A2 rotate in the same direction. The eccentric A2rotates thereon in the op osite These eccentrics`| are riven through geaE and F and a longitudinally mova le square shaft N from a coil spring Ywhich in turn receives its V and is.

to the eccentrics A2 and A2, the eccentrics B2, B2 B2 are compelled toturn (see Figs. 9 and 10) within the element W, the eccentric B2rotating in the opposite direction to the eccentrics A2, B2 and B2. Toequalize the forces acting on the element W, the eccentrics A2 and B2are together equal in weight to the total mass of the eccentrics A2, A2,B2 and B2. The element'W is thus reciprocated by the eccentrics and doesnot require any special guiding means, other than its support on theeccentrics B2, B2 and B2. The operation will be more readily understoodby reference to Figs. 9 and 10 which illustrate the position assumedwhen the eccentrics A2 and A2 have rotated through approximately 45degrees from the vertical centre line. It will be seen that theeccentrics A2 and A2 each tend .to turn within its surrounding eccentricbut that, in doing so, they react upon each other through the cross-pinR, this reaction compelling the eccentrics B2 and B2 to turn in the o psite directions to A2 and A2 respectively. Since B2 rotates in theopposite direction to B2 and B2, the element W is prevented from turningwith any of the eccentrics B2, B2 or B2. The eccentrics are so adjustedon the cross-pin R that the parts of greater radius are always in lineon the vertical centre line of the cross-pin (see Fig. 8) andconsequently the reactions on the element W reach their maximum when theeccentrics pass over their upper and lower dead centres. As theeccentrics reciprocate with the element W, they supplement the actualwei ht of the latter, which may thus be relative y negiligible. M is amembrane closure for the interior of the casing C and against which thetu V is adapted to strike.

Various ot er mechanical means may be adopted for obtaining the relativemovement between the element W and tup V, such as planet gearing, linksand the like. For supplying lubricant and in order to reduce welght theaxle Ris structed as a thin walled tu e.

Fi 13 to 16 illustrate a construction in l whic eccentrics A2 A2 B2 andB2 are employed without an element W. The eccentrics A2 and A2 aredriven in oppositedirections by gearing E interposed between theeccentrics. The eccentrics B2 and B2 are caused to rotate about theeccentrics A2 and A2 b means of the cross shaped slots E2 in whic guideblocks or rollers E2 and E2 are movable, the latter bein fixed on armsE2 carried by the eccentrics 2 and B2. In Fig.

16 the eccentric B is turned through 45. w

referably conlll Instead of the pin-and-slot connection, the movement ofthe eccentrics B1 and B2 may be effectedby planet gearing or like means.

The eccentrics in Fig. 13 rotate upon a unilaterally fixed axle orjournal R. thus avoiding the ldifficulty of forking the tup V as asupporting means.

The peripheries of the eccentrics B1 and B2 do not require to becircular. The necessary eccentricity of the centre of gravity of themasses however determines to some extent the shape of both eccentrics.

ln the construction shown in Figs. 13 to 16, the eccentrics A1 and B1are together equal in weight to the eccentrics A2 and B2 taken together.Since A1 rotates in the opposite direction to A2 and since B1 and B2must turn about A1 and A2 respectively in opposite directions, andfurthermore, by reason ofthe eccentrics. being so adjusted that theirgreatest radii are in line vertically (as seen in Fig. 14), theeocentrics react on the cross-pin R and set the latter in verticalreciprocation.

Figs. 11 and 12 illustrate a construction having a hollow axle R uponwhich rotate eccentrics A1 and A2 having teeth engagin a. driving pinionE. The eccentrics A1 an A2kare thus driven in opposite directions.Pinions F1 and F2 are carried 'internally b eccentrics B1 and B2, thepinions F, and l 2 engaging internal teeth G, and-G2 on vthe hollow axleR. In this case, also, the

eccentrics B1 and B2 are rotatable on the eccentrics A1 and A2respectively and are caused to rotate in opposite directions by thegearing F1, G, and F2, G2 and, as the greatest radii ofthe eccentricsare in line i vertically (as seen in Fig. 12) the reaction of theeccentrics on the axle R reciprocates thel latter, which carries the tupV.

The driving mechanism preferably comprises a spring Y (Figs. 2 and 8)which 1s continuously or intermittently wound up by means of a motor orby hand. The torque on the crank A (Fig. 2) or shaft E (Fig. 8) variesaccording to the degree of acceleration of the mass W and also ac-`cordin to the amplitude' of the stroke. Imme iately after the blow,considerable power is required to lift the tup. Consejuently in order toavoid strain on the prima mover or driving gear and shafts, themechanism is driven by means of a spring such as a clock spring, whichwill Avary in angular velocity to such an extent as to revent shocks.Immediately after the bow,

ing the tup to a unidirectional force.

3. A mechanical hammer as specified in ,claim 1 provided with la springacting in` a forward direction upon the tup.

4:. A mehcanical hammer as specified in claim 1 provided with a springinitially under considerable stress and acting in a forward directionupon the tup.

5. A mechanical hammer as specified in claim 1 in which the mechanismcomprises eccentric driving gear.

6. A mechanical hammer comprisin a reciprocatory tup, an inner rotatablyriven eccentric journaled on the tup and an outer eccentric mounted outhe inner eccentric.

7 A mechanical hammer comprising a reciprocatory tup, a plurality ofinner oppositely driven eccentrics journaled on the tu and a pluralityof outer eccentrics mounte on said inner eccentrics.

8. A mechanical hammer as specified in claim 6 having a weighted elementsupported by the outer eccentric.

9. A mechanical hammer as specified in claim 1 in which the mechanismimparts a rotary path to the cent-re of gravity of the movable element.

10. A mechanical hammer comprising a reciprocatory tup, a plurality ofelements movable in relation thereto and mechanism journaled in said tufor actuating said elements in o posite directions to each other.

11. A mecliianical hammer as specified in claim 1 having a spring forresiliently driving said mehcanism.

12. A mechanical hammer as specified in claim 6 in which the innereccentric is journaled on a cross pin fixed to the tup.

. 13. A mechanical hammeras specied in claim 6 in which the innereccentric is journaled on a hollow cross in fixed to the tup.,

RUDOLF OLDSCHMIDT. Witnesses:

ARTHUR SCHoLY, Go'rrLmB IscH.

Ell)

